Organisers of the annual July 1 pro-democracy march warned the police yesterday against any tightening of controls on the demonstration, expressing concerns that the upcoming Olympics and the visit of a state leader could lead to crackdowns. Releasing a survey on alleged abuse of police power, the Civil Human Rights Front also said the authorities had been targeting activists who had taken part in protests and other public functions in the past year. Front vice-convenor Jackie Hung Ling-yu warned at a press conference that the police could again deploy 'dirty tricks' on Tuesday with the aim of curbing the turnout. 'In many public protests in the past months, the police have been using dirty tricks to hinder protesters and tried to prevent people from joining,' she said. 'If officials hope to use these to curb people speaking out on July 1, it will definitely fail.' Ms Hung said the Front had yet to make plans for Vice-President Xi Jinping's visit on July 6, but she was concerned that his visit, coupled with the general tightening of security ahead of the Olympics, would mean police would be less relaxed when dealing with protesters. The protest's organisers only received notification that police had no objections to the march last night, during a meeting to discuss the details of the march. Ms Hung said the late notification would make it difficult for organisers to mount any appeals if they did not agree with any conditions imposed by police. A group survey of 25 activists arrested over protests found 12 said they have been mistreated by police. Nine said they have been shouted at, eight said they had been manhandled, and seven said they have been verbally abused. A police spokesman said the force always respected public rights.